Hello! I currently have an iPhone 2G, and I am trying to track a used iPhone down for my brother for his b-day, a gift from the whole family. Basically, I've come across a lot that aren't selling with SIMs, are deactivated (reset to default), and can't test. I have my own SIM in my iPhone. Is it possible to pop it in and do a test call on someone's deactived iPhone before I buy? Thanks!